G

Glycogen

In our effort to construct a minimal endosymbiotic metabolism in cyanobacteria we investigated the yet understudied effects of glycogen deficiency on the diurnal transcriptome and metabolome of Synechocystis. We found that cells are maladjusted to night-day transitions especially, caused by a nocturnal ATP crisis and extensive metabolic rebalancing to maintain cell viability. Among redox imbalances and evidence of carbon starvation, this includes altered regulation of the cell cycle leading to desynchronised division. This indicates that host control over the emerging endosymbiont is an immediate consequence of glycogen storage loss, and could enable further integration of the bacterial partner during organellogenesis.